PROJECT SUMMARY/ABSTRACT Emerging data indicate that the prevalence of prescription drug misuse (PDM) in adolescents and young adults is heavily influenced by school status, with higher rates of opioid and tranquilizer/sedative (i.e., largely benzodiazepine) misuse in those not in school and higher rates of stimulant use among students. Other research indicates that younger individuals not in school have more concerning substance use profiles and related consequences, with adolescent school dropouts particuarly vulnerable. That said, no research has evaluated PDM characteristics, like motives or diversion sources, by school status in adolescent and young adult prescription misusers. The long-term goal of the research team is to understand prescription misusers and PDM processes across the lifespan, aiding intervention developers by identifying treatment targets and vulnerable subgroups of misusers. In this project, using data from multiple years of the National Survey on Drug Use and Health (NSDUH), the overall objectives are to: one, evaluate differences by student status in adolescents and young adults (separately) in PDM correlates, motives, sources, types, SUD symptoms and patterns of concurrent PDM-other drug use (polydrug use); two, establish latent classes of nonmedical users, separately for the following groups: adolescent students, adolescents not in school, young adult students and young adults not in school; and three, compare latent classes on PDM characteristics (e.g., motives), polydrug use and SUD symptoms. Variable selection was guided by Problem Behavior Theory, allowing for examination of risk and protective factors for PDM across a variety of domains. The rationale for the proposed project is that better characterization of adolescent and young adult prescription misusers and PDM processes in those groups will provide clearer targets for interventions focused on PDM. The contribution of this project will be significant because it will identify especially vulnerable adolescents and young adults engaged in PDM, allowing intervention developers to better craft robust prevention and treatment programs to limit and/or treat PDM in the two age groups with the highest prevalence of PDM. Furthermore, the research proposed here is innovative because it represents a significant departure from the current state of the field focused largely on school-based samples by applying accepted techniques and analyses, all previously utilized by the research team, to considerably expand the knowledge base about PDM in a more diverse population of younger individuals. Other sources of innovation include the investigation of a nationally representative and large sample using a comprehensive set of PDM measures, dimensional examination of substance use disorder symptoms (including those from PDM) and use of a well-studied theory to study the influence of a wide variety of risk and protective factors. Rapid dissemination of the knowledge derived from this project has the potential to inform the development of maximally valid intervention options to prevent or reduce PDM and its consequences in adolescents and young adults, all of which is consistent with the mission of NIDA.